Answer:
D. "always" cover the microscope when not in use.
Explanation:
when you are finished using a light microscope or any microscope in general you always need to put the cover back on it. Mostly, to protect it from any harmful bacteria, light etc. and to keep it clean and, from collecting dust.
A C - only male expressed the disorder and only females carried the disease. This is typical of a special type of diseases where only females are and can be carriers and only men can and are affected. There aren't many diseases like this but they do exist.
